After years of development, testing, and regulatory approvals, a genetically engineered mosquito will be released in Florida. Scientists and officials in Florida have been trying to control the mosquito population there, of which about one percent is Aedes aegypti. That type of mosquito can transmit diseases including Zika and dengue, and the state has already seen cases of those viral infections.
The plan is to release 750 million mosquitos in 2021 and 2022. The mosquitoes, called OX5034 were genetically modified by Oxitec, a US company based in Britain. The idea is to control the mosquito population without using insecticides, with a kind of genetic time bomb. Only female mosquitoes bite, so the males have been engineered to carry a protein that is supposed to kill females before they reach the age when they begin to bite.
There have been some successes with the strategy. A version of Aedes aegypti males called OX513A was released in the Cayman Island in 2010, and wild populations of Aedes aegypti were subsequently suppressed by an estimated 80 percent. When OX513A Aedes aegypti males were released in a suburb of Juazeiro, Bahia, Brazil, researchers reported that the local Aedes aegypti mosquito population was reduced by 95 percent.
Unsurprisingly, people are extremely concerned with what some have called a 'Jurassic Park' experiment. Environmental organizations are worried that a genetically modified male in the wild could have unknown and unintended consequences, and may harm endangered organisms that feed on mosquitoes.
The permit that was granted by the EPA allowing the release noted that Oxitec must notify state officials 72 hours in advance of any mosquito release and that tests ensuring that females are not reaching adulthood have to be performed for at least ten weeks afterward. If the genetically modified females are found to be surviving to adulthood, the company must stop releasing them and start applying insecticides that can kill larva and adults in areas where the mosquitoes have already been released. That has to continue until OX5034 mosquitoes cannot be identified in the wild population for at least two generations.
There is reason for concern. Over 27 months, 450 thousand OX5034 males were released in Jacobina, Bahia, Brazil. Over time, a strain of mosquito emerged that was a viable hybrid between the natural local population and OX5034. That news was announced in Scientific Reports last September, and it's still unclear how this hybrid strain is impacting the transmission of disease.
Federal approval has also been granted for the release of OX5034 in Texas, but local approval has not yet been given.
In the risk assessment provided to the public by the EPA, there are redactions, suggesting that some aspects of their decision-making process have been kept secret, which unfortunately can raise questions about the nature of the approval process.
Hopefully, the release of the genetically-engineered mosquitoes will be a good thing, as mosquitoes are considered to be the world deadliest animal and are responsible for the transmission of some very serious diseases like malaria.